approving vs backup

approving and backup both are nouns.

Word	Noun	Adjective	Verb	Adverb
approving	Yes	Yes	No	No
backup	Yes	No	No	No

As nouns, backup is a hyponym of approving; that is, backup is a word with a more specific, narrower meaning than approving:

approving (noun)	backup (noun)
the formal act of approving	the act of providing approval and support
	(computer science) a copy of a file or directory on a separate storage device
	a musical part (vocal or instrumental) that supports or provides background for other musical parts
	someone who takes the place of another (as when things get dangerous or difficult)
	an accumulation caused by clogging or a stoppage

approving (adjective)	backup (adjective)
expressing or manifesting praise or approval